Clockwork driving mechanism in tachometers and the like



U. KOHLER Dec. 29, 1931.

CLOCKWORK DRIVING MECHANISM IN TAGHOMETERS AND THE LIKE Filed March 9,1951 'Umr-ao STATES-v ULRiCH KOHLER, on sw'rrz'nianniv1), AssrGNon T'HAsLnnhle-vonMALs g, VON c. HASLER, or BERN, SWITZERLAND, A 00330-RATIQNOF swrrzEnL Nn Patented Dec, 29, 1931 pmmorrmTELEGRAPHENWERKSTATTE "cnookwon'x DRIVING MECHANISM m TAGHOMETEBS ANDTHE LII-{E Application filed Mai-ch19, 1931, Seria1No. 521,376, and inSwitzerland March 15, 19.30.

This invention relates to clockwork driving mechanism in tachometers,and the like, and has for its objecttogprovide an improved constructionsuch that only a quite small predetermined tension-of the main spring isre, quired for driving the Clockwork.

According to the invention there 1s provided a clockwork drivingmechanism comprising a rotary escapernent device whereof an escapementwheel isrigidly connected with a driving wheel arranged. on a mainspringloading-shaft, and whereof a pawl s controlled by a releasing memberwhich 1s itself controlled by a part rotating with a main-spring barrel,so that when the driving or main springis loaded after a predeterminedangular movement of the part rotating with said barrel in relatio'ntothe ratchet wheel, the releasing device, becomes inoperative in relationtothe said pawl and the escapementdevice is thereby disengaged. 1

According to a feature of the invention, the pawl aforesaid isconstructed in the form of an escapement anchor and the escapementwheelas' a star wheel, the said pawl and releasing member being mountedon. a locking wheel that is fast on saidloadingshaft and is held againstrearward "rotation, Y

According to a further feature of the invention', the said pawl isformed with an extension or tail-piece that reaches tothe side of theloading-shaft diametrically opposite the pivot of the pawl, andrthereleasing memher is formed as atwo-armed lever-controlled by aretardation catch which is itself controlled in such a manner by a camon the spring barrel aforesaid that the releasing member, after release'of' the said'pawl by the retardation catch, is prevented} from returning into its locking position until, after a predetermined rotationof the camin relation to the ratchet wheel the retardation catchiscaused to release'the releasing member. i

' Other features'of the invention will be de: scribedhereinafter. andpointed out in the v claims.

One embodiment of the invention is dia ple in the accompanying drawings,where Figure 1 shows one form ofdrivingmechanism according to theinvention in side felevation as viewed from the right-hand sideofFigure2,. M v t w 1 Figure 2 is a cross-section taken on the line IIIIin Figure-1, j

1 Figure 3 is a side elevation as viewed from the left-hand side of.Figure .2, r ,Figures 4 and 5 are sections similar Figure 2, but showingvarious parts in difs ferent positions, and

Figures 6 and positions. 3 H y i 3 Like reference characters designatelike parts throughoutthe several views. A

Referring; to the drawings, a spring-barrel 2 is free to rotate onashaftl for winding orv loadingadrivingor main spring,knot shown, in thebarrel; The inner endxof this main spring is attached to the shaft 1 andits outer end is firmly connected to the-pe riphery of the barrel; Aring 3 of teeth on the barrel drives a time shaft, not shown, of aclockwork; l c h A spur gear ,4 carrying a four-point star wheel 5 isfreely rotatable on the loading shaftv land is driven by the shaft ofthe tachometer which is tobe measured. This star wheel 5 together withan escapement anchor 8 forms a rotary escapement device, the anchor 8'being mounted at, 6 on a locking wheel 7 that is faston the shaft 1andprevented from rotating backwards. The one arm of the anchor 8 has alugor tail piece 811. that extends to the side of the shaft 1diametrally opposite the pivot pin 6, whichlug hasat its free end atooth 8b. The anchor 8 with,its lug 8a 8b constitutes the pawl aforesaidof the rotary escapementdevice, Whereof'the star whee1i5 constitutes theescapement wheel.

The locking pawl 8, 8a, 8b is controlled by a two-armed releasing lever10 fulcrumed on the locking wheel 7 at 9. This releasing member 10 hasat one end an inwardly directedtooth 11. Oneuend .of a spring 10 mountedon the locking wheel 7 tendsto hold grammatically illustratedbyway-offexam the tooth 311 ofthe releasing member 10 in 7 show details invarious the path of movement of the tooth 8b of the pawl 8. The innerend position of the releasing member 10 is determined by a stop pin 13which passes with play through a hole 14 in the locking wheel 7 andengages with a lever 15 fulcrumed-also at 9 but at the other side of thelocking wheel 7. The lever 15 is controlled by a locking lever 16constituting the retardation catch aforesaid which is fulcrumed at 16 onthe locking wheel 7 The other end of the spring 10' presses inwards apin 17 of the catch 16 that extends through a hole 18 in the lockingwheel 7 and the catch. 16 is'thus held with its free shouldered end inthe path of a rise or projection 21 of a cam 20 fast on the barrel 2. A

The lever 15 has a lug 15 extending within range of the rise 21. If themain spring is loaded sufficiently and the rise 21 of the cam 20 coactswith the lug 15 (position I in Figure 7) the releasing member 10 will bedisengaged, that is moved from its position shown in Figure 2 into thatshown in Figures 4 and 7. Under the influence of the spring 10 the catch16 swings inwards at once and takes under the lever 15 so that thereleasing member 10 coupled with the lever 15 is prevented from movinginto the path of the pawl 8, 8a, 8b (and thus engaging with theescapement device) when the rise 21 of the cam moves away from under thelug 15 in consequence of the main spring starting to unwind. After thedisengagement of the releasing member the pawl 8, 8a, 8b meets with noresistance during the continued rotation of the wheel 4 and star wheel5, but swings idly to and fro between its two end positions. Thecoupling between the driving wheel 4 and barrel 2 is thus disconnecteduntil the main spring has unwound so far' that the cam 20, 21 forces thelever 16 outwards (Figure 6). Under the influence of the spring 10' thereleasingmember returns into the path of movement of the locking pawl 8,8a, 8b which is then prevented from swinging to and fro and drives thelocking wheel 7 and with it the shaft 1 under the influence ofthe mainspring. When the locking wheel 7 has rotated approximately onerevolution in relation to the spring barrel 2, and the main spring isthus fully wound up and loadedto a maximum, the rotary escapement deviceis disengaged afresh by the cam 20. 21.

When the above described clockwork drive is employed it is possible touse a definitely predetermined and small mean tension of the main ordriving spring'so that in spite of the non-uniform rotation of thedriving wheel 4 corresponding to the speed at any time of the vehicle aquite uniform driving force can be exerted on the clockwork.

The invention is not restricted to the precise constructional detailsenumerated.

I claim 1. A clockwork driving mechanism com-' prising in combination ashaft, a barrel freely rotatable about the same, a spring having one endconnected to said shaft and its other end connected to the barrel, adriving wheel on the shaft, and a rotary pawl-and-ratchet devicecomprising a ratchet-wheel firmly connected with said driving wheel, anda p awl coacting with the ratchet-wheel, a releasing member arranged toengage and be disengaged from said pawl, and amember rotatable with saidbarrel and arranged to control said releasing member so that when saidspring is loaded after a predetermined angular movement of said memberabout the shaft in relation to said ratchet-wheel, the releasing memberis moved out of engagement with said pawl and the .pawl-and-ratchetdevice thereby becomes operative.

2. A clockwork driving mechanism comprising in combination a shaft, abarrel freely rotatable about the same, a spring having one endconnected to said shaft and its other end connected to the barrel, adriving wheel on the shaft, a locking wheel free to rotate on the shaftin only one direction, a rotary escapement device comprising a starwheel firmly connected to said driving wheel, and a pawl pivoted on saidlocking wheel and coacting with said star wheel, a releasing memberpivoted on said locking wheel and arranged to control said pawl, and amember rotatable with'said barrel and arranged to control said releasingmember so that when said spring is loaded after a predetrmined angularmovement of said member about the shaft in relation to said escapementwheel, the releasing member is moved out of engagement with said pawland the escapement device thereby becomes operative.

3. A clockwork driving mechanism comprising in combination a shaft, abarrel freely rotatable thereon, a spring connected at one end to theshaft and at its other end to the barrel,'a driving wheel on the shaft,a locking wheel free to rotate on the shaft in only one direction, arotary escapement device comprising a star wheel rigidly connected tosaid driving wheel, and a pawl pivoted on said locking wheel andcoacting with said star wheel, a cam rotatable with said barrel, areleasing member in the form of a twoarmed lever pivoted on said lockingwheel and having one arm arranged to control said pawl, and aretardation catch mounted on said locking wheel and arrangedto controlthe other arm of said lever, which catch is so controlled by said camthat the releasing member, after being moved into its releasing positionin which it is disengaged from said pawl, is prevented from returninginto its locking position until, after a predetermined rotation of thecam in relation to the star wheel, the catch is caused to release thereleasing member.

4. A clockwork driving mechanism comprising in combination, a shaft, abarrel free- 1y rotatable thereon, a spring connected at one end to theshaft and at its other end to the barrel, a driving wheel on the shaft,a locking wheel free to rotate about the shaft in only one direction, arotary escapement device comprising a star wheel rigidly connected tosaid driving wheel, and a pawl pivoted on said locking wheel at one sideof the shaft and coacting with said star wheel, which pawl has atailpiece extending around said shaft to a situation opposite the pivotof the pawl, a cam rotatable with said barrel, a releasing member in theform of a twoarmed lever pivoted on said'locking-wheel,

one arm of which lever is spring pressed and arranged to lock andrelease said tail-piece,

a control member carried'by the barrel and arranged to coact with thesecond arm of said lever extending through the locking wheel, and aspring-controlled retardation catch mounted on said locking wheel andarranged to engage the said second arm of the lever and hold the latteragainst its spring out of engagement with said tail-piece, and a pin onsaid catch extending through the locking wheel and controlled ,b saidcam.

ULRICH OHLER.

